The Cook County Assessor's Office is not yet accepting property assessment appeals of 2021 assessments. For updates on when 2021 assessments will be published, and when appeals can be filed, see our calendar

When the Cook County Assessor’s Office reassesses a property (typically once every three years), its duty is to produce a Fair Market Value -- what the property could fairly sell for, between a willing buyer and a willing seller.

Appeals are a process by which a property owner can contest their property valuation.

Appeals may only be filed during certain periods. You do not need to hire an attorney to file an appeal and filing is free at our office. 

What is the Cook County Assessor's process for filing appeals?

It is the policy of the Cook County Assessor to assess all real property in a fair and uniform manner consistent with the legal responsibility placed on the Office of the Assessor. It is also our policy to provide everyone equal access to the remedies afforded by the appeal process. In accordance with these policies, the Office of the Assessor shall provide experienced personnel to assist property owners who want to appeal their assessed valuations.

All filers must adhere to the Official Appeal Rules of the Cook County Assessor

All filers are encouraged to use the expanded Online Appeals platform. 

You can read more resources we have developed for residential property appeals and commercial property appeals.

When can I file an appeal?

You will receive a reassessment notice in the mail when the Assessor's Office reassesses your property (typically, every three years). Once you have received your notice, you have 35 calendar days to file an appeal with our office. The last date to file an appeal is printed on your notice.

You may also appeal your assessed valuation in any year between reassessments when your property's township is open for appeals.

The schedule for assessments and appeals can be found here

How can I file an appeal?

Appeals can be filed online or at our offices. In 2020, the Cook County Assessor's Office greatly expanded the kinds of properties and appeals that can be filed online

You do not need a lawyer, tax representative, or appraiser to file an appeal on the assessed valuation of your home. If your appeal is filed by an authorized representative, an Attorney/Representative Authorization Form must be completed and filed along with the appeal. Note that your appeal must be filed within your township deadline, posted on our Assessment Calendar and Deadlines page.

The kind of appeal you file depends on your property type.

Property type Description
Vacant Land
(Class 1)
All vacant and unimproved real estate.
(Class 2)
All single family homes, town homes, condominiums, cooperatives, multi-family residential buildings and mixed-use property (residential and commercial) with no more than six units.
Apartments with 6+ Units
(Class 3)
Apartment buildings with 7 or more units. 
(Class 4)

All non-residential real estate owned and exclusively used by a not-for-profit corporation in the furtherance of the purposes set forth in its charter.

Commercial and Industrial
(Class 5)

Commercial: any real estate used primarily for buying and selling of good and services, or for otherwise providing goods and services, including any real estate used for hotel or motel purposes.

Industrial: any real estate used primarily in manufacturing.

Omitted Assessments  
Incentives and Other special properties You must have already filed an incentives eligibility application and be deemed eligible in order to file an incentives appeal. Eligibility applications are available in the incentives section.
Condo/Co-op For condominium parcels.